Cake:

• 9 Tbsp unsalted butter, at room temperature
• 1 cup sugar
• zest of 1 lemon
• 3 large eggs, separated
• 1 tsp vanilla extract
• 2 cups all-purpose flour
• 2 tsp baking powder
• 1 tsp salt
• 1/2 tsp baking soda
• 1 cup plain Greek yogurt (or vanilla yogurt)
• 1 1/2 cups raspberries (fresh or frozen)

Lemon Buttercream:

• 1 cup unsalted butter, at room temperature
• 5 cups confectioner’s sugar, sifted
• 4 Tbsp fresh lemon juice (adjust to taste)
• 1 small drop yellow gel food coloring (optional)